Method of making containers and lids therefor

ABSTRACT

The manufacture of a container having a lid is contemplated by the process of centrifugal casting of a closed receptacle having in one surface, an area designed to provide an opening into the interior thereof. This area is defined by a projection area which stands out from the remaining side or wall, the projecting surface in the form of a flat surface disposed generally parallel but spaced away from the remaining wall or container surface by means of a boundary wall disposed generally perpendicular to both the container wall and the flat projecting area, said wall being found so that by cutting and removing certain portions of the latter, the flat portion can define a cover for the opening to permit filling and closure of the container and subsequent removal of the product so introduced by removal of the closure.

Jan. 4, 1972 G. M. sHowALTER ET L 3,632,717

7 METHOD OF MAKING CQNTAINERS AND LIDS THEREFOR Filed Aug.- 29, 1969 INVENTORS GUY M. SHOWALTER HARRY C. SCHROEDER KERMIT GAUSE and M ATTORNEYS United States Patent US. Cl. 264-152 5 Claims ABSTRACT OF THE DISCLOSURE The manufacture of a container having a lid is contemplated by the process of centrifugal casting of a closed receptacle having in one surface, an area designed to provide an opening into the interior thereof. This area is defined by a projection area which stands out from the remaining side or wall, the projecting surface in the form of a fiat surface disposed generally parallel but spaced away from the remaining wall or container surface by means of a boundry wall disposed generally perpendicular to both the container wall and the flat projecting area, said wall being found so that by cutting and removing certain portions of the latter, the fiat portion can define a cover for the opening to permit filling and closure of the container and subsequent removal of the product so introduced by removal of the closure.

This invention is concerned with the manufacture of containers and closures therefor. It is particularly adaptable to the manufacture of containers from plastic materials. While primarily directed to the production of inexpensive shipping containers known as barrels, the method may be used to produce any variety of shapes and sizes of containers of any one of a number of materials including glass, metals and the like.

Traditionally, and also due to economics, many prod ucts including chemical powders, granulated food products, liquid active agents and the like have been shipped from manufacturer to consumer in cylindrical containers having end closures. Generally these containers are made of met-a1 fiberboard or similar materials and the end closures and interior are so lined and/or sealed as to prevent attack of the container by whatever material is being shipped and to prevent loss or contamination of the materials due to leakage. Various lining compositions are employed and various methods are used to apply the lining materials to the interiors of the containers.

It is believed quite obvious that the cost of shipping containers is a function of the process by which they are manufactured. Hence, the additional steps required to incorporate liners, by whatever process results in increased container costs, while at the same time, depending on its ultimate use, no single method of lining produces, what may be termed a standard container having general utility for the shipment of an almost unlimited variety of products in liquid, powder, granular or any such similar physical characteristics.

An object of the present invention, then, is to produce an all purpose container.

A further object of the invention is to provide a method whereby container and cover may be manufactured by centrifugal casting of plastic materials.

Still another object of the invention is to perfect a method for producing inexpensive shipping containers.

A further object of the invention is to provide a method of manufacturing a container and lid therefore in the minimum number of finishing steps.

Patented Jan. 4, 1972 "ice These and other objects not necessarily set forth but inherent in the concepts set forth may be accomplished by the steps of introducing the material to be formed into closed molds, causing the material to conform to the interior configuration of the closed walls to form a hollow receptacle, removing the molded receptacle from the molds, thereafter removing a selected portion of the receptacle by cutting away a portion thereof and thereafter reapplying the cut away portion to the remainder of the receptacle to form a removable closure.

Having set forth in general terms the inventive concepts a more detailed description is set forth hereinafter wherein reference is made to the drawings forming a part thereof and wherein:

FIG. 1 is a sectional view of a hollow centrifugally cast container.

FIG. 2 is a partial sectional view showing the container of FIG. 1 after the second step in the method.

FIG. 3 is a view similar to FIG. 2 showing an additional step in the process; which step may or may not be combined with the second step.

FIG. 4 is a view similar to FIGS. 2 and 3 and showing the lid formed by steps two and three applied to the container as, for example, after a filling operation, while FIG. 5 illustrates at least one method of locking the lid in place as would be done during shipment of the container after filling.

Considering, now, FIG. 1, it will be seen that the method comprises the formation of a typical container having a bottom 1 a continuous integral sidewall 2 and a top wall 3. For purposes of illustration, the wall 3 is provided with a lid-forming area 10 during formation of the receptacle. As shown, lid forming area 10 includes an outwardly projecting flange 4. Flange 4 is configured such that it includes an identical pair of outwardly bowed corrugation-like ribs 7 and 8. The ribs 7 and 8 extend completely around the flange 4. Rib 8 which is the outermost rib of the two terminates in an integral planar wall 11 which along with bottom 1, side wall 2 and top 3 define a closed hollow article.

While there are many materials having desirable properties for use in forming containers including glass, plastics, metal, etc., the container is illustrated herein as being formed of a plastic. It is contemplated that, because there are a variety of plastics having the properties of being thermoplastic, hence castable or moldable in heated molds; chemical inertness to most substances and, last, relative inexpensiveness as a raw material, the method would be carried out by molding or casting the desired plastic into the form shown in FIG. 1.

Again, while various procedures can be followed in forming the FIG. 1 article, one of the quickest and most economical processes is that known in the art as centrifugal casting. In this process matching mold parts are opened to permit the introduction of a thermo-responsive material therein. The mold is then closed and while being subjected to heat it is rotated about multiple axis to impart centrifugal forces thereto which distribute the raw material evenly onto every portion of the mold surfaces. Under the influence of heat applied to the molds the material is caused to get or coalesce forming an integral hollow article, The molds are finally cooled, opened and the completed article removed.

Among the number of materials that may be centrifugally cast are polyethylene compositions which are a granular or powdered material and have a very high gel temperature such that they are unaifected, and once molded, by the normal range of temperatures encountered by products during their normal use. The material is relatively inexpensive, is chemically inert to most substances, and hence, is an ideal material from which to manufacture receptacles particularly large sized whipping containers.

Thus, as is evident the first step in the present process is more or less conventional except that the molded products has no access opening.

In order to provide a means whereby the article may be used for its intended purpose, the flange 4 is now cut immediately adjacent the top of rib 7 as illustrated in FIG. 2. The result is that an opening is formed to the interior of the container said opening being bounded by a rib-like lip defined by rib 7. The removed part now comprises the planar area 11 which is bounded by the circumscribing rib 8 and in the particular configuration shown a short depending skirt 12 which was previously connected between ribs 7 and 8.

The next step is the formation of the final lid configuration. In this connection it must be noted that the configuration of ribs 7 and 8 is identical. Thus if rib 8 is cut at a point approximately at its maximum circumference there is formed a dish shaped cover having the fiat area 11 provided with a slightly dependent curved peripheral cage which will mate with the upper area of rib 7 circumscribing the mouth of the container. The very small amount of material defined by the lower half of rib 8 and skirt 12 is discarded.

As illustrated in FIG. 3 step three of the process appears to be a separate and distinct operation. It should be noted, however, that steps 2, FIG. 2 and three FIG. 3 may often be combined particularly where a large number of identical containers and covers are being formed in a single production run.

When the covers, now identified by the reference numeral 20 are to be fixed in place for shipment any number of closure devices may be used to assure against displacement. One of the easiest to use and reliable closure means is by the use of the usual cover clinch 25 as shown in FIG. These devices are simply channel shaped metal bands which are expandable and contractable in diameter by the use of a catch or latch and which would have the lower rail of the channel located beneath rib 7 and the upper rail overlying cover 20 when in contracted position around the mouth of the container.

In general containers and covers, particularly if formed of polyethylene will not require any additional sealing means to prevent leakage between cover and container. This material has some plastic fiow properties under pressure so that when the cover 20 is firmly pressed into place over the lip 7 both it and lip 7 will tend to conform to one another in the surface to surface contact area therebetween. In those instances where, however, additional sealing is desirable a sealing gasket or deposit of a typical elastomeric closure sealing material may be deposited so as to be interposed between closure 20 and the abutment area of the mouth of the container to effectively seal same during normal use.

Throughout the foregoing description it will be noted that no attempt has been made to define in detail the plan shape of the mouth of the container or in fact the configuration of the container itself. The reasons are believed obvious. Nonetheless it should be noted the process is equally eflfective in the formation of almost any container regardless of configuration. It is equally effective to form wide mouth, or small mouthed containers;

4 oval, circular, square or any other type of access opening, hence, the process is not limited in its application to a particular configuration of intermediate or final product.

Having thus described the invention, what is claimed is:

1. The method of manufacturing plastic containers and closures therefor comprising the steps of (a) forming a closed, hollow container structure in a mold, while (b) simultaneously providing on the closed structure an outstanding projecting area including two, spaced identical in the form of annular corrugations each having an inwardly facing bight portion and parallel annular leg portions, said ribs being spaced apart by an intermediate, cylindrical, spacer portion,

(c) thereafter cutting completely through the projecting area at the intermediate, cylindrical spacer portion along the upper edge of the one of said ribs closest to the remainder of the container, leaving said rib integral with the remainder of said container to form a mouth therefor including a flat annular area bounding said mouth,

((1) additionally, cutting through the second rib diametrically in a plane passing through said rib at the greatest diametric dimension thereof to thereby form a separate disc-like cover having a downwardly curved, peripheral lip comprised of the portion of the rib left integral with the cover,

(e) removing the severed and integrally attached cylindrical, intermediate and residual remaining rib from between the severed cover and container,

(f) placing the disc-like cover on the mouth of the container with the disc-like portion and the downwardly curved edge of the cover in engagement with said mouth as defined by the first-mentioned rib and overlapping the peripheral edge of the mouth and the annular bounding portion and at least a portion of the bight of said rib,

(g) thereafter clamping said closure in position to close the mouth of the container.

2. The method defined in claim 1 wherein the plastic is polyethylene.

3. The method defined in claim 1 wherein the cutting operations are combined.

4. The method defined in claim 1 wherein a seal is interposed between the closure in the mouth of the container.

5. The method defined in claim 1 wherein the closed receptacle is formed by centrifugal casting.

References Cited UNITED STATES PATENTS 3,409,710 11/1968 Klygis 264l52 3,165,565 1/1965 Cox 264-3l1 3,292,252 12/1966 Reading 264-l52 3,187,381 6/1965 Britten 264311 ROBERT F WHITE, Primary Examiner R. H. SHEAR, Assistant Examiner US. Cl. X.R. 

